Shield
Soldier
Gate
Tower
Chat with our AI personalities
to get into n castle you have to beat the elite 4
once you beat the game castle fairfax will be available to buy for 1,000,000 gold
You have to beat the Level 5 castle in mini Mario form.
All you need to do is beat the Industrial Castle level. Make sure you have a sandwich on you to open the door at the beginning of the level.
If you mean battle him, you do that after you beat N in N's Castle.